Implantable medical devices are commonly used to provide electrical stimulation to body tissues, monitor physiologic conditions, and provide alternative treatments to drugs. Examples of implantable medical devices include implantable cardio defibrillators, pacemakers, and programmable neuro-stimulator pulse generators, which are collectively referred to herein as implantable medical devices or IMDs. IMDs typically incorporate a hermetically sealed housing enclosing a power source and electronic circuitry. The sealed housing is also known as a “can.”
A header assembly is connected to the can. The header assembly includes a generally cylindrical receptacle for a medical lead cable. The receptacle includes spaced electrical contact elements that are electrically coupled to the electronic circuits or to the power source located inside the can via conductive terminals or leads. The header assembly provides a means for electrically communicating, via the external medical lead cable, between the electronic circuits or power source located inside the device and the area on the anatomy where the stimulation is applied.
In one preferred embodiment, the electrical contact elements are canted coil springs within circular conductive housings. The electrical contact elements have elastomeric seals in between them to prevent the intrusion of body fluids from affecting the electrical performance of the IMD.
Industry-wide standards have been adopted for, among other things, the dimensions, contact spacing, etc. for the medical lead cable and the receptacle. Furthermore, it is desirable to maintain good electrical contact between the header assembly and the medical lead cable during the life of the implantable medical device. It is not desirable for the medical lead cable to disconnect from the receptacle, because it would then be impossible to provide electrical stimulation to the stimulation site. However, it is desirable for the medical lead cable to be removable from the receptacle while implanting and/or programming the IMD, and for replacing the IMD when necessary.
The following U.S. patent applications provide further information regarding connector assemblies for use with implantable medical devices: Ser. No. 12/100,646, filed on Apr. 10, 2008; Ser. No. 12/102,626, filed on Apr. 14, 2008; Ser. No. 12/062,895; filed on Apr. 4, 2008; and 61/171,043, filed on Apr. 20, 2009.